U.S. patent application number 11/084324 was filed with the patent office on 2006-09-21 for diffusion plate and grate assembly for a gas burner.
This patent application is currently assigned to BSH Home Appliances Corporation. Invention is credited to Gayle B. Collins, Michael Gerdes, Manfred W. Staebler.
Application Number | 20060207588 11/084324 |
Document ID | / |
Family ID | 37009014 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060207588 |
Kind Code |
A1 |
Staebler; Manfred W. ; et
al. |
September 21, 2006 |
Diffusion plate and grate assembly for a gas burner
Abstract
A gas burner and grate combination includes a gas burner
constructed for being operated at least at a high intensity level
and at a low intensity level. A grate is located relative to the
gas burner for supporting a cooking utensil thereon. A diffusion
burner plate is located above the gas burner spaced from a cooking
utensil when a cooking utensil is positioned on the grate. The
diffusion burner plate is of a size such that when the gas burner
is operated at a high intensity level the flame length is long
enough to reach beyond the edges of the diffusion burner plate, and
when the gas burner is operated at a low intensity level, the flame
is contained under the diffusion burner plate such that heating of
the cooking utensil occurs by radiation. In a further aspect, a
cooktop includes the described gas burner and grate
combination.
Inventors: |
Staebler; Manfred W.; (New
Bern, NC) ; Gerdes; Michael; (New Bern, NC) ;
Collins; Gayle B.; (New Bern, NC) |
Correspondence
Address: |
JOHN T. WINBURN
100 BOSCH BOULEVARD
NEW BERN
NC
28562
US
|
Assignee: |
BSH Home Appliances
Corporation
Huntington Beach
CA
|
Family ID: |
37009014 |
Appl. No.: |
11/084324 |
Filed: |
March 18, 2005 |
Current U.S.
Class: |
126/215 ;
126/39E |
Current CPC
Class: |
F24C 15/10 20130101;
F24C 15/107 20130101 |
Class at
Publication: |
126/215 ;
126/039.00E |
International
Class: |
F24C 15/10 20060101
F24C015/10 |
Claims
1. A gas burner and grate combination, comprising: a gas burner
constructed for being operated at least at a high intensity level
and at a low intensity level; a grate located relative to said gas
burner for supporting a cooking utensil thereon, for having food
therein cooked through operation of the gas burner; a diffusion
burner plate located above the gas burner at a location for being
spaced from a cooking utensil when a cooking utensil is positioned
on said grate forming an air gap there between, and of a size
wherein when the gas burner is operated at a high intensity level,
the flame length is long enough to reach beyond the diffusion
burner plate, and when the gas burner is operated at a low
intensity level, the flame is contained under the diffusion burner
plate and heating of the cooking utensil occurs by radiation
thereby avoiding hot spots which occur at low intensity levels.
2. The gas burner and grate combination of claim 1, including said
diffusion burner plate constructed integral with said grate.
3. The gas burner and grate combination of claim 1, including said
diffusion burner plate including means for being removably attached
to said grate.
4. The gas burner and grate combination of claim 1, including said
gas burner having a burner cap and said diffusion burner plate
located above said burner cap.
5. The gas burner and grate combination of claim 1, including said
diffusion burner plate including a central opening or aperture
therein.
6. The gas burner and grate combination of claim 1, including said
diffusion burner plate is formed in a solid element.
7. The gas burner and grate combination of claim 1, including said
diffusion burner plate is formed with perforations therein.
8. The gas burner and grate combination of claim 1, including said
diffusion burner plate shaped to conform to the shape of the gas
burner.
9. The gas burner and grate combination of claim 1, including said
diffusion burner plate made from one of a metal and a ceramic
material.
10. The gas burner and grate combination of claim 1, including said
diffusion burner plate formed of a thickness and width selected for
causing simmering of foodstuffs in a cooking utensil when said gas
burner is operated at an intensity level where the length of the
flames from said burner does not extend beyond an outer edge of
said diffusion burner plate.
11. The gas burner and grate combination of claim 1, including
fingers extending from said grate for supporting said diffusion
burner plate thereon.
12. The gas burner and grate combination of claim 1, including said
diffusion burner plate shaped to not conform to the shape of the
gas burner.
13. The gas burner and grate combination of claim 1, including said
diffusion burner plate is located sufficiently spaced from a
cooking utensil when a cooking utensil is placed on said grate to
ensure that substantially all heating occurs by radiation with
substantially no heating by conduction occurring.
14. The gas burner and grate combination of claim 1, including said
diffusion burner plate formed in one of a substantially flat, a
concave or a convex shape.
15. A cooktop, comprising: at least one gas burner constructed for
being operated at least at a high intensity level and at a low
intensity level; at least one grate corresponding to said at least
one gas burner located relative to said at least one gas burner for
supporting a cooking utensil thereon, for having food therein
cooked through operation of the gas burner; at least one diffusion
burner plate located above the gas burner at a location for being
spaced from a cooking utensil when a cooking utensil is positioned
on said grate forming an air gap there between, and of a size
wherein when the gas burner is operated at a high intensity level,
the flame length is long enough to reach beyond the diffusion
burner plate, and when the gas burner is operated at a low
intensity level, the flame is contained under the diffusion burner
plate and heating of the cooking utensil occurs by radiation
thereby avoiding hot spots which occur at low intensity levels.
16. The cooktop of claim 15, including said diffusion burner plate
constructed integral with said grate.
17. The cooktop of claim 15, including said diffusion burner plate
including means for being removably attached to said grate.
18. The cooktop of claim 15, including said gas burner having a
burner cap and said diffusion burner plate located above said
burner cap.
19. The cooktop of claim 15, including said diffusion burner plate
including a central opening or aperture therein.
20. The cooktop of claim 15, including said diffusion burner plate
is formed in a solid element.
21. The cooktop of claim 15, including said diffusion plate burner
is formed with perforations therein.
22. The cooktop of claim 15, including said diffusion burner plate
shaped to conform to the shape of the gas burner.
23. The cooktop of claim 15, including said diffusion burner plate
made from one of a metal and a ceramic material.
24. The cooktop of claim 15, including said diffusion burner plate
formed of a thickness and width selected for causing simmering of
foodstuffs in a cooking utensil when said gas burner is operated at
an intensity level where the length of the flames from said burner
does not extend beyond an outer edge of said diffusion burner
plate.
25. The cooktop of claim 15, including said diffusion burner plate
is formed in one of a substantially flat, a concave or a convex
shape.
26. The cooktop of claim 15, including said diffusion burner plate
shaped to not conform to the shape of the gas burner.
27. The cooktop of claim 15, including said diffusion burner plate
is located sufficiently spaced from a cooking utensil when a
cooking utensil is placed on said grate to ensure that
substantially all heating occurs by radiation with substantially no
heating by conduction occurring.
28. The cooktop of claim 15, including a plurality of gas burners
and a plurality of said grates corresponding to said plurality of
burners.
29. The cooktop of claim 29, including a plurality of diffusion
burner plates corresponding to said plurality of gas burners.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a combination gas burner
and grate assembly with a diffusion burner plate assembled
therewith for limiting heat transfer to a cooking utensil such as a
pot when the burner is operating at low intensity levels. This
arrangement eliminates hot spots typically created by low intensity
level burners, while having little to no effect on heat transfer at
high intensity levels.
BACKGROUND OF THE INVENTION
[0002] Current cooktops employing gas burners have been used
commercially and residentially for a number of years. As the
construction of such cooktops, both as standalone, built-in,
slide-in or drop-in cooktop appliances as well as a part of free
standing ranges has evolved, the amount of energy generated by such
cooktops has increased, both when employed at the lowest burner
intensity settings, as well as at the highest burner intensity
settings. In fact, cooktops designed for residential use today are
approaching the capabilities of commercial units, including
generation of the high BTU's possible with such commercial units.
This has led to a number of problems when burners on such cooktops
are used at lower intensity levels, or at the lowest intensity
levels, for example, for simmering food items in cooking utensils
such as pots.
[0003] More specifically, the problem with the use of such burners
at low intensity levels is that there is not a uniform distribution
of energy due to relatively short flame length and thus, this
generally creates selected hot spots in the cooking utensil while
attempting specialized cooking operations such as simmering. As a
result, simmering does not occur uniformly and portions of the food
being cooked may tend to burn or to be cooked excessively, while
other portions are not sufficiently cooked.
[0004] In the past, numerous attempts have been made to distribute
the energy from gas burners in a more uniform manner. One attempt
to do so involves placing a diffuser plate directly on the grate
with which a burner is used so that the flames coming from the
burner are not allowed to contact the cooking utensil. Such an
approach avails itself of the fact that heating of the cooking
utensil occurs by conduction which occurs as a result of the flames
impinging on the diffuser plate and causing heat to be conducted
through the diffuser plate to the cooking utensil. This approach is
suitable for a low burner flame operation, but is not suitable for
a high flame operation.
[0005] More specifically, if the diffuser plate is made too thick
and is separated sufficiently from the burner as a result of being
placed above the grate, there may be insufficient energy transfer
to the cooking utensil when the burner is operated at low intensity
levels. Conversely, if the diffuser plate is made too thin, due to
the imperfect nature of how heating of the diffuser plate and
conduction occurs, there could still result a number of localized
hotspots, which also occur when a diffuser plate is not used. More
specifically, depending on materials selected for the diffuser
plate, conduction is generally not uniform. While there may be
materials from which the diffuser plate could be made in which
conduction could more evenly occur, such materials would make
construction of the diffuser plate prohibitively expensive.
[0006] One alternative approach has been to provide a jet
impingement/radiation plate which functions to transfer heat from a
burner to a cooking utensil both by radiation and by jets produced
by jet holes in the plate. Such a plate is generally mounted
directly below a grate of a burner and while attempting to create
radiant heat, still has the problems of creating hotspots
particularly because conduction occurs from the plate to the grate
directly and therefrom to the cooking utensil. Similarly, the fact
that hot combustion products, i.e., burning gas, pass through the
many openings in the plate to impinge upon the bottom of the
cooking utensil also causes the problem of localized hotspots.
[0007] Other approaches have involved various deflector
arrangements in an attempt to enlarge the area of flame impinging
on cooking utensil. All of these approaches suffer from the
afore-mentioned problems.
[0008] These and other problems of the prior art are avoided in
accordance with the present invention in which a system is provided
for limiting heat transferred to a cooking utensil when a burner is
operating at low intensity levels, and providing heating at the
lower intensity levels substantially through radiation with little
or substantially no conduction occurring, while having little or no
effect on heat transfer when the burner is operated at high
intensity levels.
BRIEF SUMMARY OF THE INVENTION
[0009] In accordance with one aspect of the invention, there is
provided a gas burner and grate combination, which includes a gas
burner constructed for being operated at least at a high intensity
level and at a low intensity level. As will be appreciated by those
of ordinary skill in the art, such burners are also capable of
being operated at intermediate levels between the highest and the
lowest intensity level depending on the amount of opening of a
valve providing gas to the burner.
[0010] A grate is located in association with the gas burner for
supporting a cooking utensil thereon and for having food therein
cooked through operation of the gas burner. Such a cooking utensil
can take various forms including pots, pans and various other
containers for food. A diffusion burner plate is located above the
gas burner at a location for being spaced from a cooking utensil
when a cooking utensil is positioned on the grate. The diffusion
burner plate is of a size such that when the gas burner is operated
at a high intensity or at levels, which are higher than the lowest
intensity level as appropriate, the flame length is long enough to
reach beyond the diffuser burner plate. When the gas burner is
operated at a low intensity level, i.e., typically at the lowest
intensity level and selected levels higher than the lowest level,
depending on the size selected for the diffuser burner plate, the
flame is contained under the diffusion burner plate and heating of
the cooking utensil occurs substantially by radiation. This avoids
hot spots, which occur at low intensity levels. Alternately, there
can be a central opening or hole in the diffusion burner plate
which can provide both radiation and a controllable amount of heat
transfer directly to the cooking vessel through the central
opening.
[0011] The diffusion burner plate can be constructed integral to
the grate or with means for being removably attached to the grate
such as, for example, with clips. The removably attached diffusion
burner plate can be utilized with burners that were not originally
fitted or made with a diffusion burner plate. Further the diffusion
burner plate can just loosely rest on fingers provided on the
grate, so the diffusion burner plate easily can be lifted off of
the grate for cleaning.
[0012] The diffusion burner plate can be constructed in various
forms to conform to the shape of the burner or to be different from
the shape of the burner. The diffusion burner plate can be made of
metal or a ceramic material and can be of different shapes such as
concave or convex. For example, in the case of a star shaped burner
the diffusion burner plate can be star shaped or circular. The
diffusion burner plate can also be perforated, but not sufficiently
to allow flames to reach through the burner plate to the cooking
utensil, with the exception of ones designed with the central
opening therein.
[0013] In a yet still further aspect, the invention relates to a
cooktop, which includes at least one gas burner and grate
combination with a diffusion burner plate as previously described.
The cooktop preferably includes a plurality of gas burners and a
corresponding plurality of grates, or a single large grate,
corresponding to the plurality of burners and with at least one
diffusion burner plate on one of the gas burner and grate
assemblies. In a yet still further aspect, the cooktop can include
a plurality of diffusion burner plates corresponding to the
plurality of gas burners. By the term plurality is meant at least
two, and in most typical cooktop constructions, at least four and
in some cases six to eight aforementioned combinations.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of the gas burner and grate
combination illustrating the diffuser burner plate of the present
invention mounted thereon;
[0015] FIG. 2 is a top plan view of the gas burner and grate
combination of FIG. 1;
[0016] FIG. 3 is a side partial cross-sectional view of the gas
burner and grate combination of FIG. 1 showing the diffusion burner
plate with the gas burner in operation;
[0017] FIG. 4 is a side partial cross-sectional side view of the
gas burner and grate combination showing for illustration purposes
only the diffusion burner plate operating as one half of the
operation and with the other half without the diffusion burner
plate, both with the gas burner in operation;
[0018] FIG. 5 is a side partial cross-sectional view of the gas
burner and grate combination showing another embodiment of the
diffusion burner plate with a central opening and with the gas
burner in operation;
[0019] FIG. 6 is a side partial cross-sectional view of an
alternate embodiment in which the diffusion burner plate is
removably mounted to the grate by a plurality of clips; and
[0020] FIG. 7 is perspective view of a cooktop having multiple gas
burners and illustrating a pair of gas burner and grate
combinations, each with a diffusion burner plate of the present
invention mounted thereon.
DETAILED DISCUSSION OF THE INVENTION
[0021] FIGS. 1 and 2 illustrate a gas burner and grate combination
11 in accordance with the present invention. A gas burner 13 is
associated with a cooking utensil support such as a grate 15, as
conventionally used on gas cooktops, as is well known by those of
ordinary skill in the art. A diffusion burner plate 17 is disposed
between the gas burner 13 and the grate 15 and attached to the
grate 15. The diffusion burner plate 17 is sized or dimensioned so
that gas flames (see FIG. 3) emanating through apertures 19 of the
gas burner 13, when the burner 13 is operated at the lowest or
lower intensity levels, will not extend beyond a peripheral edge 20
of the diffusion burner plate 17 and instead will impinge directly
on the bottom of the diffusion burner plate 17 to achieve radiant
heating of a cooking utensil such as a pot which may be placed on
the grate 15 (see FIG. 3), without any substantial amount of
conduction of heat to the cooking utensil. By the term lowest or
lower intensity levels is meant low heat or the approximate lowest
flame intensity for the burner 13 to maintain.
[0022] FIG. 3 illustrates one embodiment of the present invention
and its operation at both high fire 23 on the left and low fire 21
on the right. This operation is only for purposes of illustration
as the gas burner 13 in normal operation emits a substantially
uniform flame around a periphery 22 thereof. In this Figure, the
diffusion burner plate 17 is directly connected to the grate 15,
preferably below or at the lowest level of the grate 15 so as to
create an air gap 27 between the diffusion burner plate 17 and the
cooking utensil 25. When the gas burner 13 is turned on at the
lowest or a low intensity level (low fire illustrated on the right
side of FIG. 3), the flames 21 resulting from gas discharged
through the ports 19 are contained beneath the diffusion burner
plate 17. Heating of the cooking utensil 25 occurs as a result of
conduction 29 which heats up the diffusion burner plate 17 to cause
heat 31 to radiate through the air gap 27 up to the cooking utensil
25 to promote substantially uniform heating, substantially without
hotspots of the cooking utensil 25. When the gas burner 13 is
turned onto a high or higher intensity level (high fire illustrated
on the left side of FIG. 3), the length of the flames extend as
flames 23 beyond the edge 20 of the diffusion burner plate 17 and
therefore the diffusion burner plate 17 does not interfere with
direct heating 34 of the cooking utensil 25 at the higher intensity
levels. By the term high or higher intensity level is meant high
heat or the approximate highest flame intensity for the burner 13
to maintain in a normal operation.
[0023] It will be appreciated that some conduction 29 occurs
through the grate 15 to the diffusion burner plate 17 as a result
of the diffusion burner plate 17 being directly attached thereto,
but this is a substantially minimal effect.
[0024] In the embodiment of FIG. 3, and FIGS. 1 and 2, the
diffusion burner plate 17 is shown permanently mounted to the grate
15 by any means appropriate as will be readily apparent to those of
ordinary skill in the art. The diffusion burner plate 17 can be
permanently mounted to the grate 15 by numerous methods, such as
welding, mechanical fasteners, such as screws or rivets or a
mechanical interlocking feature like a bayonet twist. The diffusion
burner plate 17 also can be integrally made or formed with the
grate 15, such as by casting.
[0025] In accordance with FIG. 4, for illustration purposes only,
the diffusion burner plate 17 is illustrated operating as one half
of the operation 30 (left side) and with the other half of the
operation 32 (right side) a standard burner operation without the
diffusion burner plate 17, both with the gas burner 13 in a simmer
operation producing the low flame 21. In the diffusion burner plate
17 operation 30, heat 36 from the flames 21 is convectively
transferred to the diffusion burner plate 17, which in turn
radiates heat 31 from the diffusion burner plate 17 to the utensil
25. In the standard operation 32, heat 38 from the flames 21 is
convectively transferred directly to the utensil 25, with minimal
conductive heat loss. Both operations 30 and 32 have minimal
conductive heat loss into the grate 15.
[0026] In accordance with FIG. 5, another embodiment of the present
invention is illustrated, in this case, the diffusion burner plate
17' includes a central opening 33. The central opening 33 is
dimensioned to provide some direct convective heat transfer through
the diffusion burner plate 17' to the utensil 25. This may enhance
the heating of a central portion 35 of the utensil 25 and also can
reduce the weight of the diffusion burner plate 17'.
[0027] Although the diffusion burner plates 17, 17' have been
described as being attached permanently or substantially
permanently to the grate 15, the diffusion burner plates 17, 17'
also can be separate from the grate 15 and can just rest on the
grate 15. This also is illustrated in FIG. 5, where the diffusion
burner plate 17' is a separate element and rests on a plurality of
fingers or lips 42 which are secured to or formed with the grate
15. The fingers 42 can be welded or integrally formed with the
grate 15. Although not illustrated, the diffusion burner plate 17'
also could have projections formed thereon which allow the
diffusion burner plate 17' to rest on the grate 15. In that case
the grate 15 would not be formed with the fingers 42. In either
case, the diffusion burner plate 17' easily can be removed from the
grate 15 just by lifting the diffusion burner plate 17' off of the
grate 15, such as for cleaning purposes.
[0028] In accordance with FIG. 6, an alternative construction of
the present invention is shown, in this case, the diffusion burner
plate 17 is mounted onto the grate 15 by way of a plurality of
clips 33 which can allow for removal of the diffusion burner plate
17 in selected instances as may be appropriate for the user. Also
the clips 33 allow the diffusion burner plate 17 to be added to
cooktops to which it was not provided for as a retrofitting of the
cooktop. While the clips 33 are illustrated, as will be readily
apparent to those of ordinary skill in the art, other equivalent
means for mounting the diffusion burner plate 17 can be employed.
What is important is that the air gap 27 between the diffusion
burner plate 17 and the bottom of any utensil 25 placed on the
grate 15 is maintained. Further the air gap 27 is sized to provide
the most efficient radiant heating of utensils 25 at low intensity
levels of operation of the gas burner 13. The air gap 27 and the
diameter of the diffusion burner plate 17 are optimized for the
diameter of specific burners 13, BTU rate, the design of the burner
ports 19, type of fuel, etc. Generally the diameter of the
diffusion burner plate 17 is the most critical factor as long as
the air gap 27 is present. Generally an air gap 27 on the order of
at least two (2) to three (3) millimeters is sufficient for
operation with the diffusion burner plate 17. The upper limit of
the air gap 27 depends upon the desired operation of the cooktop
and the type of burner utilized.
[0029] In a yet still further aspect of the present invention,
there is shown in FIG. 6 a cooktop 37 having multiple gas burners
13 thereon and a single integral grate 15 used for all the gas
burners 13. Such a cooktop 37, as previously described, can be a
standalone cooktop with the burners 13 mounted in a cabinet (not
illustrated), or can be part of a combination standalone range with
an oven (not illustrated). Typically, such cooktops include at
least four burners and in some cases up to six or eight burners.
The cooktop 37 can be assembled with only one diffusion burner
plate 17 or with multiple diffusion burner plates 17 either
removably attached or permanently affixed thereto as previously
described.
[0030] As implemented, the diffusion burner plate 17 of the present
invention reduces the net effect of energy transfer to the cooking
utensil 25 when a gas burner 13 is operated at low intensity levels
without substantially reducing the net energy transfer when the gas
burner 13 is operated at high intensity levels.
[0031] As previously discussed, the diffusion burner plate 17 does
not come into contact with the cooking utensil 25 so that heat
transferred to the utensil 25 is substantially only by radiation
from the diffusion burner plate 17 without substantial conduction
transfer. As a result, hot spots typically found on low intensity
settings of the cooktop are avoided by even distribution of the
energy over a larger surface of the cooking utensil 25.
[0032] In various alternative constructions, the diffusion burner
plate 17, 17' can be perforated as previously discussed. The
diffusion burner plate 17, 17' can be thick or thin in design as
will be readily apparent to those of ordinary skill in the art, and
optimized for operation with a selected cooktop and/or gas burner
and grate combination with which it is to be used. In terms of
shape, the diffusion burner plate 17, 17' can be substantially
flat, convex or concave in shape as appropriate to optimize
performance. Another advantage of the use of the diffusion burner
plate 17, 17' is the operation is independent of the type of gas
burner utilized.
[0033] In terms of material utilized to make the diffusion burner
plate 17, it can be made from metal or from ceramic or from other
appropriate material as will be readily apparent to those of
ordinary skill in the art. The diffusion plate burner 17 diameter
may be optimized in size to allow a range of settings for the lower
intensity settings for the gas burner 13. The diffusion burner
plate 17 can conform to the shape of the gas burner 13 with which
it is used or can be of a different shape. For example, a round gas
burner 13 may have a round diffusion burner plate 17 and a star
shaped gas burner 13 may have a star shaped diffusion burner plate
17. In other cases the diffusion burner plate does not conform to
the shape of the gas burner 13, for example, a round gas burner 13
could have a star shaped diffusion burner plate 17. Other examples
of shapes include triangles or squares. Any of shapes of the
diffusion burner plate 17 can include the central aperature 33.
[0034] Having thus generally described the invention, the same will
become better understood from the appended claims in which it is
set forth in a non-limiting manner.
* * * * *